This invention relates to alignment mechanisms in general, and more particularly to an improved X, Y, .theta. alignment mechanism, particularly useful in alignment of optical apparatus. In copending U.S. application, Ser. No. 339,860 filed Mar. 9, 1973 and assigned to the same assignee as the present invention, an optical projecting and scanning apparatus useful for producing integrated circuits is disclosed. In such an apparatus, the alignment between a mask and a wafer is required. That is to say, both the wafer and the mask must be translated in two orthogonal directions and rotated about their respective centers in order to align the wafer with the image of the mask. If such is not done without cross-coupling, the operator can become confused and alignment may take an undue amount of time. In addition, proper alignment requires very fine adjustment in the order of a micron.
Thus, it is the object of the present invention ot provide such an alignment mechanism which has negligible cross-coupling and which, at the same time, permits the fine adjustment required.